How to resolve makzonb error

Hi,
When performing dynamic analysis using 3DEC 9.0 to simulate an earthquake, I selected free-field boundary conditions. After the model was cut by DFN, an error message appears, stating “makzonb error: 0 zone vol -1.4636E+04” (as shown in the image). However, this error does not appear when using viscous boundaries. Could you please explain the reason for this issue and how to resolve it?
Thank you in advance!
JLUJYP

Probably the program has a hard time making free-field boundaries when there are joints that extend to the boundaries. Please send the data file to 3decsupport@itascacg.com and we can look at it. In the short term, you can try cutting your DFN so that there is a layer of uncut blocks around the outside.